fitting 850\'s in the primary fuel rail

leeroy_25 · May 27, 2009, 09:22:44 PM

I read somewhere that you need to mod the primary fuel rails to fit 850cc secondary injectors in? I just got a set out and they appear to drop straight in other than the tip sits slightly further up inside the body?

Can someone confirm if need to make a mod I haven\'t spotted or if what I read was a load of rubbish!? or I mis-read it of course!

Thank you
Lee

antnicuk · May 27, 2009, 09:39:57 PM

you will hear conflicting stories, the mod is to machine 2-3 mm (definitely no more than 3) off the top of the holder so the injectors sit lower, if you do too much the injector wont seal inside. Its easy to do but i know of people who just put them in without the mod and say they work fine, i did the mod and they ran just like stock ones. If you imagine the injector spray pattern, if it sprays higher up inside the holder the fuel will hit the inside of the holder and not be in a nice mist when it goes into the engine.

HTH

leeroy_25 · May 27, 2009, 09:49:47 PM

So it was what noticed about the injector sitting further up inside the body! I don\'t know what the mist pattern is like so how much the housing would actually mess up the spray I don\'t know? Surely machining the top down to make the injector drop lower means you might start to obscure the fuel coming in or blow it up past the top seal instead of throguh the injector? would want to measure up very carefully before doing anything like that.. If it works fine without then there seems no sense in messing about with them. plus if I ever want to swap back at a later date and just wap in some huge secondaries I don\'t need to hunt around for a new injecor holder!

Is it not possible to take 2mm off the other end that goes into the engine or maybe taper the opening further inside?

Some more views would be nice. but thank you for yours..

Cheers
Lee

leon · May 28, 2009, 11:18:53 AM

I\'ve looked into this myself as its somthing i want to do shortly, (Dont have the milling tools sadly

) The yanks bless em have mentioned that they put an extra O ring onto the injector if they dont modify the rail as there have been instances of it not sealing and spreying fuel out into the engine bay!

Nik da Greek · May 28, 2009, 11:29:33 AM

Mine\'s just away at Super 7 having this done as we speak. I know Jason said he had to make some modification to the fuel rail to make it work, he was going to make one up before I dropped the car off and then just swap them over to save time. Not sure exactly what the modification was though, soz. Not being much help am I? I was going to visit the car today if I get time, I\'ll ask him

shaunwil · May 28, 2009, 06:35:09 PM

Strange. I turned a bush and swapped the o-ring over to a different size and they have been fine. Although the Fuel rail is my own design too :Giggle

Shaun

ashc · May 28, 2009, 07:18:54 PM

i have heard that there is a chance they will leak without the rail being thinned, and you don\'t want any change really, however small!

Nik da Greek · May 28, 2009, 07:22:06 PM

Well, that didn\'t work out so well! Went to visit the car, but she was away on the dyno, so didn\'t get a chance to ask about the technique J used on mine :Hammer! Early results from the dyno cell indicate that it bloody works, though, whatever it is!

Silverstone Autosport · May 28, 2009, 07:48:23 PM

hi we have a couple of injector bodys machined and ready to fit 850\'s if your keen give kayleigh a call she will sort you out
thanks dwayne

slingo · May 28, 2009, 09:48:54 PM

Quote from: Silverstone Autosport;611586hi we have a couple of injector bodys machined and ready to fit 850\'s if your keen give kayleigh a call she will sort you out
thanks dwayne

can you get a good safe map on 4 x 850\'s with a single ?

shaunwil · May 28, 2009, 10:11:15 PM

Are you guys talking about bored out side feeds or siemen top feeds with a custom rail ??

Shaun

slingo · May 28, 2009, 10:24:44 PM

stock 850 side feeds iirc

leeroy_25 · May 29, 2009, 01:38:34 PM

Stock 850\'s is correct..

I spoke to reworx and that\'s all they said I need for my requirements.

Dwayne - I have a spare rail and access to a mill so was planning to DIY the job.. unless you want to do a dirt cheap exchange on your machined rail i\'ll do that once I confirm what I need to do!
can you say if it is just 2mm machined off the top face? What\'s your number in case I change my mind anyway!

Cheers
Lee

slingo · May 29, 2009, 05:44:35 PM

what tubby size are you going for lee ?

Speedworks · May 29, 2009, 07:27:52 PM

what if you remove the black spacer between the iron and the prim fuel rail piece?
or replace the spacer with a thinner one?

fitting 850\'s in the primary fuel rail

ashc